CHAPTER VII. 



MILK. 



MILK, as the first and natural food of man, has been 

 used from the remotest antiquity of the human race. 

 It is produced by the females of that class of ani- 

 mals known as the mammalia, and was designed by 

 nature as the noui ishment of their young ; but the 

 richest and most abundant secretions in common use 

 are those of the cow, the camel, the mare, and the goat. 

 The use of camel's milk is confined chiefly to Africa and 

 to China, that of mares to Tartary and Siberia, and that 

 of goats to Italy and Spain. The milk of the cow is 

 universally esteemed. 



Milk is an opaque fluid, generally white in color, 

 having a sweet and agreeable taste, and is composed of 

 a fatty substance, which forms butter, a caseous sub- 

 stance, which forms cheese, and a watery residuum, 

 known as serum, or whey, in cheese-making. The 

 fatty or butyraceous matter in pure milk varies usually 

 from two and a half to six and a half per cent. ; the 

 caseous or cheesy matter, from three to ten per cent. ; 

 and the serous matter, or whey, from eighty to ninety 

 per cent. 



To the naked eye milk appears to be of the same 

 character and consistence throughout; but under the 

 microscope a myriad of little globules of varied forms, 

 but mostly round or ovoid, and of very unequal sizes, 



